Arch shape cross section plastic chambers have been widely used for receiving and dispersing waters when buried in soil or other media. Examples of such chambers are shown in U.S. Pat. Nos. 4,759,661 and 5,511,903 to Nichols. Typically, chambers are about 4–8 feet in length. They have mating opposing ends, so that like chambers may be connected end to end at joints where there is overlap of one chamber by the adjacent chamber. The joint fit is sufficient to prevent entry of soil and other media. Preferably, the chambers latch together in some positive way, so the overlap fit is not lost, by vertical motion of one chamber relative to the other. See U.S. Pat. No. 5,336,017 to Nichols for an example of chamber joints.
However, sometimes the nature of the terrain for a desired installation requires that chambers be installed as non-straight rows. In such situations, a bend in a string of chambers can be accomplished by use of chambers or adapters which have angled ends. See U.S. Pat. No. 5,588,778 to Nichols et al. and U.S. Pat. No. 5,669,733 to Daly et al. More preferably, chambers may be constructed with ends that enable the installer to make one chamber overlay the next, with the long axes running at chosen angle, within some range, for example plus or minus 10 degrees. Sometimes, such types of chambers are referred to as swivel-end chambers. Examples of such chambers, which are sometimes referred to as swivel-end chambers, are shown in U.S. Pat. No. 6,592,293 to Hedstrom et al., U.S. Pat. No. 6,375,388 to Zoeller et al., and U.S. patent application Ser. No. 10/442,810 of Burnes et al.
However, one of the problems attending the previously known so-called swivel end chambers is that there can be a tendency for one chamber to lift off from the other, before the chamber string is backfilled. That can undesirably allow media to enter the chamber string through the resultant gap, which can lead to problems with ingress of material over time during use. Such an adverse condition may be avoided by careful installation, or by the use of mechanical screw fasteners of the like, to attach one chamber to the other once the chambers are laid in place at the desired angle. However, installers may often not take adequate care. They may be annoyed by the nuisance and increased labor which attend the use of mechanical fasteners. Fasteners may not be timely installed, before material gets into the joint. Slight adjustment after fastening is not possible unless the fasteners are removed. Thus there is need for improvements in chambers to overcome the nuisance problem.